1. Technical Field
The present invention relates to a spectroscopic image acquiring apparatus and a spectroscopic image acquiring method.
2. Related Art
In the related art, a Fabry-Perot interference filter (an interference filter) which causes a pair of reflection films to face each other and causes a predetermined wavelength among incident light beams, which is strengthened by being multiply interfered by the pair of reflection films, to transmit therethrough has been known. In addition, an imaging apparatus which is provided with such an interference filter, an imaging element, and an imaging optical system which forms an image on the imaging element by using the light transmitting through the interference filter, and captures a spectroscopic image is known (for example, refer to JP-A-2009-141842).
Incidentally, in an interference filter which is capable of changing a size of a gap between the reflection films, the gap size may be not uniform due to the deflection of a substrate or a reflection film at the time of changing the gap size, a manufacturing error, or the like in some cases. In this case, there is a problem that light beams having different wavelengths arrive at each pixel of the imaging element, and thereby it is difficult to acquire a highly precise spectroscopic image.
In contrast, a method of acquiring the wavelength of the light received in each pixel of each of the imaging elements in advance, and then sequentially changing the size of the gap between the reflection films so as to acquire a predetermined wavelength in each pixel has been considered.
However, in the above-described method, when detecting the light of each target wavelength which transmits through the interference filter by using only a single order of a peak wavelength (for example, a second peak wavelength), if an acquisition target wavelength band is large, the size of the initial gap between the reflection films is required to be large, and thus it is difficult to perform gap control.
In contrast, it is possible to resolve the above problem by setting the acquisition order with respect to the target wavelength among light beams which transmit through the interference filter. For example, a first wavelength band in a range of 400 nm to 600 nm detects the light transmitting through the interference filter as a second peak wavelength, and a second wavelength band in a range of 620 nm to 700 nm detects the light transmitting through the interference filter as a first peak wavelength. However, in this case, the gap size corresponding to each of the target wavelengths is required to be set corresponding to each of the imaging pixels, and thus an amount of change of the gap size (a driving amount) increases, thereby increasing the number of times of measurement. Accordingly, there is a problem in that it takes a long time to perform the measurement.